When tracking the movement of RFID tagged materials, such as inventory, using RFID enabled mobile structures, such as a fork lift, it is desirable to know when the materials have been loaded onto the mobile structure and when the materials have been unloaded from the structure. Determining such knowledge can allow an RFID reader to be activated or deactivated at an appropriate time.
To achieve this knowledge, some embodiments use manual intervention to activate or deactivate the RFID reader once the materials are loaded or unloaded from the mobile structure. Manual intervention, however, tends to slow the pace of mobile structure operators and is prone to human error. Other embodiments use automated techniques that utilize sensors to determine when materials are loaded on or unloaded from mobile structures. These techniques, however, do not account for the numerous unique situations that can occur in a warehouse environment, such as when workers walk in front of the sensors, the swaying and rocking of material as it is transported, and the inherent noise and false readings present in most distance measuring devices.
Accordingly, there is a need for an improved approach to determining whether a material is positioned on or off a mobile structure.